In one known machine line manufactured by ourselves, a first sheet of rectangular glass is washed, in a vertical position, in a special washing machine, rinsed, dried and passed to a so-called tilt applicator. The tilt applicator is a ball castor table which has a pneumatic mechanism for moving the glass sheet from a vertical arrival position to a horizontal working position in which the sealing strip is applied to the perimeter of the sheet. Next, another like sheet is placed on the strip, and then the assembly of two sheets with the sealing strip therebetween is passed to a roller press where it is heated to soften the sealant and compressed.
This known machine line works well and has enjoyed appreciable commercial success. Nevertheless, it is recognized that the tilt applicator, being manually operated, is not as productive as it might be. Moreover, the application of the sealing strip, also being a manual operation, requires a high level of operator skill and concentration.
Still further, the sealing strip is a component that, ideally, should not be handled at all. Thus the moisture in the form of perspiration which is inevitably present on the operator's fingers is apt to close the pores of the sealing strip which may reduce the effectiveness of the desiccant and/or deposit grease where the sealing strip is in contact with the glass; these factors could lead to the rejection of the assembled unit because of the appearance of moisture between the internal faces of the sheets of the unit and/or a reduction in the quality of the seal between the sealing strip and the glass.
Also, sealing strip is supplied in a variety of widths for correspondingly varying spacing between the two sheets of a sealed unit, and the wider the strip the more difficult it is for the operator to manipulate it and to apply it in a straight line.
In our known tilt applicator the glass sheet is rotated by hand in order to apply the sealing strip to all four sides of it and it would be desirable to provide mechanised turning in order to increase productivity.